Evaluate whether high frequency ventilation is superior to standard mechanical ventilation in providing ventilatory support for premature infants. As a participating clinical center, University of Washington will work with other clinical centers, a coordinating center, and the NIH to develop a protocol and manual of operations for the trial. University of Washington will then enroll at least seventy premature infants into the trial, collect the data as specified by the manual of operations, and transmit the data to the coordinating center. Finally, they will work with the other clinical centers and the coordinating center to analyze and interpret the results.